Improvement in the treatment of paper and paper-pulp



rHo uas rnrton, or GROVE END ROAD, ENGLAND, ASSIGNOR To EDMuNn s, HANNA.AND WALDIMER A. SCHMIDT, or PITTSBURG,'PA.

IMPROVEMENT IN THE TREATMENT OF PAP-ER AND PAPERPULP.

' Specification forming part of Letters Patent No. 114,880, dated March16, 1871.

the nature and principles of 'my said improvement, by which my inventionmay be distinguished from others of a similar class, to-

gether with such parts as I claim and desire to secure by LettersPatent-that is to say:

The object of this invention is to prepare paper or paper-pulp (eithersized, unsized, or partially sized) in such manner as to produceachange, more or less complete, in the fiber or material of which thepaper is composed, whereby the texture and character of the paper arealtered. The paper thus treated becomes less porous, acquires increaseddensity,

strength, stifl'ness, and durability, resists the action of water, andmay be made to assume, to a greater or less extent, the toughness,

semi-transparency, and general appearance of parchment, the peculiarefi'ect thus produced upon paper being, as regards chloride of zinc, anew fact in chemical science.

My invention consists in soaking paper, when dry, in a concentratedneutral, or nearly neutral, solution of chloride of zinc, either at thenatural temperatureof the air, or moderately heated, and afterwardthoroughly washin g the paper in water. I

The following is the general processI adopt I take a solutionof the saltcalled chloride or muriate of zinc, and having rendered it as neutral asmay he by the addition of oxide or carbo'uate of zinc, I concentrate thesolution 1 by evaporating ituuti-l it has acquired, when cold,the-consistence of sirup. In this case it will have the specific gravityof 2l00 or thereabont. The solution of zinc being thus prepared, Iimmerse or-floatupon its surface the paper to be treated until it isfully'satu rated with the solution, Thepaper is then 'withdrawn,-and theadhering liquor being re-. moved-by a scraper, roller, or any other me-Ychanical means,iti's eitherimmediatel y plun gcd into water or allowedto remain for a short time until it is apparently dry, then plunged intowater and washed therein until all soluble matter is removed. In caseswhere it is desirable to retain a.portion of oxide of zinc in the paper,the paper, after being partially washed, is immersed in a weak solutionof a carbonated alkali and afterward thoroughly washed in water. Thepaper may then be pressed and dried, and submitted to the ordinaryprocesses for obtaiuingasmooth or glazed surface, or it may be sized orcolored.

After this treatment it will be found that the paper is more or lesschanged, has conless. porous than before, while, at the same time, it ismuch stronger. When, however, it is desired that a more complete changeof zinc should be moderately heated before immersing the paper, or thepaper, after having been drawn through the cold solution, and theadhering liquor removed, should be exposed to a gentle heat. Thetemperature necessary may be varied from 80 to 90 Fahrenheit to littleshort of boiling water, according to the effect that is desired to beproduced on the paper. It must also be borne in mind in determining theamount of heat to he applied that the kind of paper used, its thickness,density, the strength of the zinc solution, and the length of timeduring which'the paper is exposed to heat, influence the result. Ingeneral I find that when ordinary blotting-paper is used, and the paperis heated by the application of metallic surfaces, a temperature of 120to 140 Fahrenheit is suficient. 'A good criterion of the completion ofthe change is to be found in the circumstance that the paper becomessomewhat swollen and apparently, dry. It also passesfrom a semitransparent and rather rigid state to one that is more opaque andflaccid, ,The heating of the paper may be efi'ected in several ways,first, by bringing the solution of zinc to the required temperature;secondly, by laying the saturated paper upon smooth heated surfaces, orby passing such surfaces over it, as is done in the operationof ironing.

web this may be conveniently eflectedbypassiug the paper between heatedrollers, or

through a hot chamhcr,as is commonly done tracte'd in volume, becomemore dense, and is.

should be produced in the paper, the solution When the paper is in theform of a continuous in the drying of paper; in fact, thewholeoperntion, from the first plunging the paper into the bath ofchloride of zinc to its final washing in water, may be made a,continuous process. I do not, however, claim any pa-rtiouler form ofapparatus for doing this, as.

stances in a state. of solution, and aftenwerd submit the paper tothorough washing with. Witter.v v

If sheets of paper, after having been sutu-i rated with chloride ofzinc, be pressed firmly together,-und a warm iron passed over them, thesurfaces will become permanently united,

and in this way many sheets may be joined together, or vessels formed ofone continuous piece.

Having thus described the net-are of 111 y said invent-ion, end-themanner intvhich the same is to be performed, I declare that I claim---The employment of a concentrated solution of chloride of'zinc, eitheralone or mixed with other substances, to sized or unsized paper,

and afterward'washing the paper in water,

substcntiallyin manner and :for the purposes hereinbefore described.

In testimony whereof Lhave signed my name to this specification in thepresence of two subscribing witnesses this 3d day of March, .1871.

. THOMAS TAYLOR.

Witnesses:

CHAS. D. ABEL, Juo. Bu. MILLARD.

